The present invention relates to an improved method of preserving hair and body treatment compositions and preserved hair and body treatment compositions.
Hair and body treatment compositions generally contain a preservative which is supposed to effectively protect the composition from infection by microorganisms.
Conflicting demands are made on a preservative for use in hair and body treatment compositions. Thus, on the one hand, it should be favorably tolerated in physiological and dermatological respects and, on the other hand, should possess a good germ inhibiting or even germ killing action. These two demands are usually very difficult to reconcile.
The usual preservatives used in hair and body treatment compositions are e.g. formaldehyde (a), 5-bromo-5-nitro-1,3-dioxane (b), p-hydroxybenzoic acid ester (c), 2,4,4,-trichloro-2,-hydroxydiphenylether (d), 5-chloro-2-methyl-3-isothiazolone (e), 2-methyl-3-isothiazolone (f), and 2-bromo-2-nitropropane-1,3-diol (g).
Recently, some preservatives, such as formaldehyde and 2-methyl-3-isothiazolone, have been suspected of not being sufficiently tolerated. It is known with respect to aldehydes and phenols having a preservative action that they react with proteins or interact with them in a denaturating manner. In addition, there is the risk of sensitization with aldehydes.
Another risk of using such preservatives is the danger of nitrosamine formation. In raw materials containing nitro groups ((b)+(g)), this risk is particularly high when they are used together with other nitrogen-containing components of the cosmetic composition.
Preservatives which do not have the aforementioned disadvantages have already been suggested.
For example, a hair and body cleansing composition is described in DE-OS 3 644 473 which contains a physiologically tolerated salt of formic acid, salicylic acid or its salt, and a physiologically unobjectionable organic or inorganic acid.
However, the use of salicylic acid as preservative is not completely satisfactory, since the salicylic acid can lead to skin rashes with very sensitive people or in exceptional cases to asthma attacks. Moreover, they have a keratolytic effect when used in higher concentrations, which means that they can dissolve the callous layer of the skin.